diff --git a/src/mux_h2.c b/src/mux_h2.c
index 457df083f..f6a653396 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -5069,8 +5069,10 @@ static int h2_process(struct h2c *h2c)
 		if (h2c->glitches != prev_glitches && !(h2c->flags & H2_CF_IS_BACK))
 			session_add_glitch_ctr(h2c->conn->owner, h2c->glitches - prev_glitches);
 
-		if (h2c->st0 >= H2_CS_ERROR || (h2c->flags & H2_CF_ERROR))
+		if (h2c->st0 >= H2_CS_ERROR || (h2c->flags & H2_CF_ERROR)) {
 			b_reset(&h2c->dbuf);
+			h2c->flags &= ~H2_CF_DEM_DFULL;
+		}
 	}
 	was_blocked |= !!(h2c->flags & H2_CF_DEM_MROOM);
 	h2_send(h2c);